The invention relates to a constant velocity fixed joint having a hollow outer member with a central cavity whose inner face, in meridian planes, is provided with first and second outer running grooves. The running grooves extend along the longitudinal axis of the outer member and alternate sequentially on the circumference. An inner member is arranged in the central cavity of the outer member. The inner member has a spherical outer face which, in meridian planes, is provided with first and second inner running grooves. The grooves extend along the longitudinal axis of the inner member and are positioned opposite the respective first and second outer running grooves. Together the inner and outer grooves are designed to be jaw-like towards one of the two open ends. For torque transmitting purposes, each set of opposing outer and inner running grooves jointly accommodate a ball which is guided radially in windows of a cage arranged between the outer face of the inner member and the inner face of the outer member. The track bases of the first outer running grooves and those of the first inner running grooves are undercut-free starting from one open end. The track bases of the second outer running grooves and those of the second inner running grooves are undercut-free from the opposite open end.
U.S. Pat. No. 3,133,431 discloses a joint with tracks for torque transmitting balls. The tracks may optionally be undercut-free towards the two open ends. The joint is designed as a plunging joint. For a joint with cage, the tracks extend in a straight line. For a cageless joint, the tracks, in addition to extending at an angle in the meridian plane, are curved in a plane extending at a right angle to the meridian plane. Only when the tracks extend in a straight line is it possible for the tracks to be undercut-free. However, the design principle permits only small articulation angles and short plunging distances in order to permit assembly and to prevent the components from falling apart.
GB-PS 847 569 describes a fixed joint with torque transmitting balls and tracks extending in meridian plane. The tracks extend with a radius. The radii of the track bases of two track pairs open in opposite directions and are offset relative to the joint center. The joint has a ball guiding cage designed as a hollow spherical dish. The cage and the outer part and inner part of the joint are provided with concentric spherical faces for mutually guiding each other. The ball tracks and the guiding track for the cage are undercut and therefore cannot simply be produced by precision forming.
In the case of the said design principles, the forces acting on the cage are to be offset by the alternate openings of the tracks for the ball. However, this does not happen in all operating conditions because the contact of the balls in the tracks over the entire range of articulation angles changes, which inter alia results in a change of direction of the load applied to the cage, thus placing the cage in an unstable position. Joints whose tracks extend in a straight line in meridian planes are subject to a further disadvantage in that, towards one end of each track, the track depth which is decisive for the torque transmitting capacity is decreased considerably.
It is the object of the present invention to provide a joint which is suitable as a fixed joint for large articulation angles, which even at large articulation angles has a high torque transmitting capacity and whose outer and inner members may be produced in a non-chip forming way by precision forming.